Gymnema (Gymnema sylvestre)

Brief Background:

Gymnema leaves have been used for more than 2,000 years in India to treat madhu meha, or "honey urine." It has been used alone and as a component of the Ayurvedic medicinal compound, "Tribang shila," a mixture of tin, lead, zinc, Gymnema sylvestre leaves, neem leaves (Melia azadirachta), Enicostemma littorale, and jambul seeds (Eugenia jambolana).

Preliminary human evidence suggests that gymnema may be efficacious for the management of serum glucose levels in type 1 and type 2 diabetes, as an adjunct to conventional drug therapy, for up to 20 months. Gymnema appears to lower serum glucose and glycosylated hemoglobin (HbA1c) levels following chronic use, but may not have significant acute effects (1). Some of the available research has been conducted by authors affiliated with manufacturers of gymnema products. High-quality human trials are lacking in this area (2; 3; 4).

There is also early evidence suggesting possible efficacy of gymnema as a lipid-lowering agent. Gymnema was shown in one study to possess antimicrobial action against Bacillis pumilis, B. subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus but not against E. coli and Proteus vulgaris (5).

One of the major side effects or actions of gymnema is taste alteration. Studies have shown that gymnema reduces the perception of sweetness inside the mouth and seems to increase the perception of bitterness by neural inhibition (6; 7; 8; 9; 10; 11; 12).

Expert Opinion and Folkloric Precedent:

Gymnema leaves have been used for more than 2,000 years in India to treat madhu meha, or "honey urine." It has been used alone and as a component of the Ayurvedic medicinal compound, "Tribang shila," a mixture of tin, lead, zinc, Gymnema sylvestre leaves, neem leaves (Melia azadirachta), Enicostemma littorale, and jambul seeds (Eugenia jambolana). Traditional healers observed that chewing the leaves of gymnema resulted in a reversible loss of sweet-taste perception.

The plant has also been used in African healing traditions; for example, Tanzanian healers used it as an aphrodisiac. Other traditional applications include use as an anti-malarial agent, digestive stimulant, laxative, diuretic, and snake venom antidote.

Gymnema sylvestre is a woody, climbing plant native to India. The leaves are most commonly used medicinally, although the stem is also believed to possess some pharmacological action. The leaves have been used for over 2,000 years in India to treat madhu meha, or "honey urine." Chewing the leaves was noted to diminish the ability to discriminate sweet tastes, which along with hypoglycemic properties may have prompted the Hindi name gurmar, or "sugar destroyer." Gymnema has a long history of use in individuals with diabetes.

Extracts of gymnema are widely used in Australian, Japanese, Vietnamese, and Indian folk medicine. Gymnema preparations modulate taste, particularly suppressing sweet taste sensations, and are used in the treatment of diabetes mellitus and in food additives against obesity and caries. Gymnema has become a popular natural product used in the management of blood sugar levels in individuals with diabetes and is believed by some to play a role in reducing serum lipids (41).

Reference
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